The mechanisms and regulatory factors that control the development of oligodendrocytes and the synthesis of myelin are poorly understood. The present project represents the next steps in our ongoing research on the regulation of oligodendrocyte development by 3','5 -cyclic AMP (cAMP), using tissue cultures of oligodendrocytes and oligodendrocyte precursors from rat brain. In previous studies, we have shown that cAMP analogs and agents that elevate intracellular cAMP accelerated the development of oligodendrocytes and increase the expression of myelin proteins, lipids and mRNAs. In our first specific aim, we will complete ongoing studies on the regulation of myelin proteins 2',3' cyclic nucleotide 3'phosphohydrolase (CNP), myelin basic protein (MBP), myelin proteolipid protein (PLP), DM-20 protein and myelin-associated glycoprotein (MAG) under uninduced and cAMP-induced conditions. Second, we will use antibodies to cAMP and quantitative single-cell cytofluorimetry to determine whether there is an endogenous increase in intracellular cAMP levels in glial cells as they develop into oligodendrocytes in the absence of experimental inducers. Third, we will use the specific cAMP antagonist, the Rp-diastereomer of adenosine 3'-5' cyclic phosphorothioate (Rp-cAMPS), to determine whether elevation of intracellular cAMP is a necessary precondition for oligodendrocyte development. Fourth, we will identify agonist that induce the intracellular production of cAMP in oligodendrocytes and precursors. And fifth, we will used an in vitro model system of autoimmune demyelination in aggregate cultures to determine whether cAMP analog or agents that elevate intracellular cAMP can be used to promote remyelination. These studies will define the mechanisms by which the regulatory molecule, cAMP, induces the activity of myelin-related genes i oligodendrocytes; clarify how oligodendrocyte development is regulated; and utilized this information to test possible procedures for promoting remyelination.